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Dynamic Vapour Sorption
Dynamic vapor sorption (DVS) is a gravimetric analysis, gravimetric technique that measures how quickly and how much of a solvent is absorbed by a sample: such as a dry powder absorbing water. It does this by varying the vapor concentration surrounding the sample and measuring the change in mass which this produces. Water vapor is most commonly used, but it is also possible to use a wide range of organic solvents. Dr Daryl Williams, founder of Surface Measurement Systems Ltd, invented Dynamic Vapor Sorption in 1991 and the first instrument was delivered to Pfizer UK in 1992. DVS was originally developed to replace the time and labor-intensive desiccators and saturated salt solutions to measure moisture sorption isotherm, water vapor sorption isotherms. Water sorption isotherms The main application of DVS is to measure water sorption isotherms. In general, a vapor sorption isotherm shows the :wikt:equilibrium, equilibrium amount of vapor sorbed as a function of steady state relativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravimetric Analysis
Gravimetric analysis describes a set of methods used in analytical chemistry for the quantitative determination of an analyte (the ion being analyzed) based on its mass. The principle of this type of analysis is that once an ion's mass has been determined as a unique compound, that known measurement can then be used to determine the same analyte's mass in a mixture, as long as the relative quantities of the other constituents are known. The four main types of this method of analysis are ''precipitation'', ''volatilization'', ''electro-analytical'' and ''miscellaneous physical method''. The methods involve changing the phase of the analyte to separate it in its pure form from the original mixture and are quantitative measurements. Precipitation method The precipitation method is the one used for the determination of the amount of calcium in water. Using this method, an excess of oxalic acid, H2C2O4, is added to a measured, known volume of water. By adding a reagent, here ammoni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |